Tenant fried my grage panel

45 Replies

My tenant called me a month ago to complain that he has burned up three TVs and he thought the electrical in the house was faulty. I tested the outlet and it was around 119 to 120. I put in a new outlet and told him to use a good surge protector.

He called me again the other day and said the garage lights were glowing bright and blowing out, and the garage door opener did not work. We called an electrician and we soon found that the tenant had wired and installed a compressor in the garage without my permission. The electrician said the compressor “fatigued the system” of the entire house. The compressor was wired directly into the garage box instead of a plug and had other code violations. Now I have to get a new main panel and garage panels.

Their lease is coming up for renewal and I will be billing them for part of this and I am wondering if I should ask them to leave. 

What sort of compressor are we talking about?  Something like this:

http://www.harborfreight.com/8-gal-2-hp-125-psi-oi...

Or more like this:

http://www.harborfreight.com/5-hp-60-gallon-165-ps...

If it just a little one there should be no reason it should "fatigue" the wiring.  I don't buy that explanation anyway.  A big one could potentially overload the system.  But an overload would simply pop breakers or fuses.  If a device overloaded the system such that the panels were damaged, there's a serious problem with your wiring.   That's a VERY dangerous situation that needs to be corrected at your expense. 

I would tell the tenant that any wiring needs to be done by a licensed professional, with your permission and permits.  A licensed electrician would evaluate that situation and may determine your wiring cannot sustain the load from a large compressor.  If so, the tenant would need to pay for additional upgrades if they want to install this large load.

Its the bigger one.  I think he is doing work for other than his family which our lease also prohibits. 

Your garage panel is probably a sub-panel that is taken from the main panel. Inside the main panel, there should be a breaker that limits the load that is delivered to that sub-panel. If there is no such breaker, then that is a problem. That breaker should trip if you overload the garage circuits, so maybe that breaker has too high of a trip level or maybe it is defective. 

Can you post photos of the insides of these "fatigued" panels?  Again, since the breaker did not trip, the load had to be within acceptable levels or there is a defective breaker. 

Is it possible that he wired it in a manner that bypassed the breakers?

@Shawn Thom  - if this is truly a sub-panel that has been properly wired, then it would feed from a breaker in the main panel. So even though it's possible to bypass the breakers in the sub-panel, but the one in the main panel should still be in the circuit. 

If you had had a discussion at lease signing that was recent about no mods without written authorization, i would not renew. if the guy acts like its his house and he should be able to do whatever he wants and that you can pay when he messes up, i would not renew. its interesting he had you come out while the compressor hookup was in plain view.

I'm really, really skeptical that wiring a compressor to a garage subpanel had any impact at all on the main panel or the rest of the house.  If it did, you have some seriously bad wiring and this guy probably did you a favor, because it would have caught fire eventually.

@Steve Babiak  

In a sfr it is legal to essentially overload the system, with assumptions about usage allowing it. You can put up to 200A of breakers in a 100A panel, or 400A of breakers in a 200A panel (as long as the main breaker is right). So assume they did that, and the compressor's 22A took the garage panel right to the 60A limit that it's main breaker allows. Now you potentially have 40A left before highly stressing the system. Are you really sure it isn't possible? Not saying that is the case, too many unknowns, but especially if it was improperly wired, it might have been drawing more than it should and maxing the 60A breaker and taking the house circuit to the max. And even if it was a 200A main panel, add an electric dryer, AC and stove and you are right back at that theoretical danger zone. 

Originally posted by @Walt Payne:

@Steve Babiak  

In a sfr it is legal to essentially overload the system, with assumptions about usage allowing it. You can put up to 200A of breakers in a 100A panel, or 400A of breakers in a 200A panel (as long as the main breaker is right). So assume they did that, and the compressor's 22A took the garage panel right to the 60A limit that it's main breaker allows. Now you potentially have 40A left before highly stressing the system. Are you really sure it isn't possible? Not saying that is the case, too many unknowns, but especially if it was improperly wired, it might have been drawing more than it should and maxing the 60A breaker and taking the house circuit to the max. And even if it was a 200A main panel, add an electric dryer, AC and stove and you are right back at that theoretical danger zone. 

 But I think Steve's point, which I agree with, is that if the main panel was wired (or breakers configured) wrongly, than legal or not that is the real issue and tough to pin on the tenant.

@Richard C.   That was my point. It may be perfectly legal, and within code, though depending on what circuits were on the main panel it could become dangerous under the wrong circumstances. If so, that is an issue, certainly, but not necessarily improper. 

And the improper wiring of the compressor could easily make the difference. I couldn't say without seeing it, but what I do know is that a licensed electrician said so after inspecting the panel, and I know that what that electrician said is reasonable. Therefore I would be inclined to accept his evaluation.

The bottom line is that this is just a residential house. the garage is for parking cars and some light power tools. It was never meant to be a small shop. Here are some pictures of the box and offending compressor at another forum:  

http://www.diychatroom.com/f18/electrical-surge-205338/index3/#post1392228

Is there a way to post pictures here?

Mark Forest yes, you can post pictures.  Use the picture icon at the top of the text box.  Third from the right end, looks like two mountains.

That's a relatively large load, but nothing excessive.  Looks like there was space in the garage sub panel for an additional breaker for this load.  Nothing wrong with direct wiring it, though that exposed romex is against code.  If this was wired with a new breaker and not just directly to the bus bars it shouldn't be a problem.  I can't tell how its wired from your pictures.  If this was too large of a load, some breaker should have popped.  Maybe the main in the garage sub panel, maybe the breaker in your main panel that feeds the garage.  I don't at all buy some "fatigue" explanation.  If this resulted in damage rather than just a breaker popping, you had some other problem before he did this.  I think you need to have a different electrician have a look.  I would charge the tenant for correcting the wiring for the compressor, but I would cover whatever damage occurred as a result of this.  And be thankful it didn't turn into a fire.

Some people think garages are for cars.  But using them for a workshop is very common.  That's what mine is for.  I don't have a compressor this large, but I do have large metal working tools with dedicated 220 volt circuits.

Jon what "other problem" do you mean?  When we worked on this house using electric saws and such we had no problems.  When the tenants first moved in before they bought this monster compressor there were no problems.   To me everything points to this thing they put in my garage without my permission.  What else could it be?

@Steve Might  if the existing wiring was all done correctly and working correctly then adding this compressor would not have caused any problems.  It may not have worked because it exceeded the capacity of the garage subpanel or the breaker for the feed to the garage sub panel.  That would have simply results in the breaker popping in the subpanel or in the main panel.  Nothing would have been fried or damaged.

So, the fact something was damaged indicates there was an existing problem somewhere.  I find the "fatigue" explanation total BS.  I also suspect you DO NOT have to replace either panel.  At the very least, I would get another electrician to look at the situation.

Some brands of older panels are notorious for failing after some years.  Older houses were also wired for lower total loads than current demands.  But breakers are there to protect against overloads.  If you overload a circuit, a breaker is supposed to open and protect the wiring.  The fact something else happened and that lights are flickering means there some problem.  Could be as simple as some of the connections in one box or the other being loose.  They can loosen over time, especially if there is any aluminum wiring.  Could be bad existing breakers.  Could be a near short somewhere (e.g. frayed or damaged insulation) that completely broke down when the higher current was demanded.  Could be some breaker was mis-sized.  For instance, the breaker in the main box should be sized based on the wire that's going to the garage box.  If, say, there is a 100 amp breaker feeding the garage (that's what I have) you would need to have #2 wire running to the garage.  Its possible that at some point there was a smaller breaker and small subpanel and someone upgraded it and replaced the breaker and sub panel without replacing the wire.  Now you put a big load in the garage.  The breaker's don't pop, but the wiring is now overloaded.  Higher currents mean more heating.   More heat, especially if wires are running through a conduit or other enclosed space means insulation can melt or scorch.  That can create a short where none existed before.   Without being there are looking at the situation, its impossible to say. 

I have seen some horrible existing wiring.  Working on a rental I opened up a wall to find in-line splices in cables buried in the wall.  Illegal by current codes.  When working on my house last year I discovered one circuit had been grounded by running a piece of bell wire over to a complete different circuit.  Who knows what's going on behind your walls.

Now, it is possible the tenant did something dumb and just wired the circuit for the compressor incorrectly and did damage the panel in the garage.  Even so, the main panel breaker should have popped and protected the wiring.

if all he did was miswire his compressor, I would think the compressor would have been damaged not the panel. Hard to believe the compressor would've burned up the panel, and as @Steve Babiak  mentioned, not even trip a breaker.  What were the other code violations?

Steven

The wiring to that sub-panel from the main panel is not correct (at least to recent NEC).  Grounds AND neutrals must be kept separate for ANY sub-panel; this sub-panel only has 3 wires feeding in, so ground and neutral are not separate.  Don't ask me why that is since they end up tied together in the main panel anyway, but that is what the code requires for (modern) sub-panel wiring.

Can you get a better picture of the wiring in that panel's lower left hand corner?  I'm trying to see if the wires to the compressor are both on one of the double pole breakers or not.  If it is split across two breakers (improper wiring) then neither breaker would trip for certain.

Originally posted by @Jon Holdman:

Now, it is possible the tenant did something dumb and just wired the circuit for the compressor incorrectly and did damage the panel in the garage.  

And that is why I forbid tenants from working on my houses.  He is required by the lease to contact me in writing to get permission.  I would then have had an electrician look at the panel, at the tenant's expense, to determine if his monster size compressor was viable .  Now he will make excuses as to why it is not his fault. 

Mark Forest the neutral conductor is a current carrying conductor.  The ground wire is not.  It only carries a current if there is a fault.  Yes, they are tied together in the main panel, and tied to a ground rod driven into the ground.  These have to be separated in a sub panel so the neutral remains the current carrying conductor.  If you tie them together in a sub panel, there are two paths from the sub panel to the main and current will flow along both all the time.

You need to call a different electrician.  This guy is either an idiot or a thief. The idea that this compressor damaged the main panel is laughable. There may be other problems - that subpanel is loaded with violations and if the person who worked in there also worked in the main panel then you could have issues in there as well - but your electrician didn't say that. He said fatigue. 

The compressor draws 15 amps. Even if it wasn't working properly and was drawing between 15 and 20 amps and was also incorrectly wired by overfusing a 15 amp wire (#14) with a 20 amp breaker, it still wouldn't harm anything in either panel. Yes it would tend to overheat the conductors feeding the compressor but that wouldn't effect the lights. 

However, based on the issues evident in the picture, there may be other problems that could account for the symptoms. Brighter than usual lights could mean extra voltage. Extra voltage also could fry electronics or motors. It is possible to wire a circuit or circuits such that extra voltage could be present. 

You need a licensed electrician that can trouble shoot. 

As an aside, is that rust in the bottom of the panel? If it is you need to find out how water is getting in there and repair that issue as well. A rusty panel needs to be replaced and the cause of the rust needs to be addressed. 

Steve, take a deep breath and count to ten.  The guy you should be worried about here is the electrician, not the renter.

The renter broke your rules and by all means be peeved about that.  But he didn't fry your entire house.  

I put some of your comments to my electrician.  He stated that the tenant could have worn out the breaker if he kept tripping it.  Breakers will only trip so many times.  If the breaker ceased to trip then all that power would "back feed."  Yes the box was old and that is why I did not want him putting this cable in it.  Had he treated the garage as just a place to park his car and maybe some light power drills that would have been fine.  

This electrician comes highly recommended by another landlord. 

The house is only a 100 amp service.  It has a well, central air, etc.  The electrician seems to think this all made a difference. 

If there was short circuit current present, and the compressor breaker failed in the closed position (I've never seen this as breakers are designed to fail open) either the subpanel feed breaker would have tripped or the main panel breaker would have tripped.  If it was just an overcurrent, and the compressor breaker failed in the closed position, the compressor may have been damaged, and perhaps the conductors supplying the compressor may have gotten a little warm (or melted if the current was significantly higher than the ampacity -current carrying capacity- of the conductor but still less than the rating of the subpanel feed breaker), but it still wouldn't effect either panel. 

A backfeed is possible under certain conditions but it requires incorrect wiring (which is possible, considering who did the wiring).  But without knowing exactly how the tenant wired the compressor, it's hard to say if this was the case. However, remember that panels are designed to handle voltages and currents. I still don't see how a backfeed of 120 volts and 15 amps could cause damage to the panels themselves. 

As far as the panel being 100amps, keep in mind that each phase can supply up to 100 amps. So you really have 200amps of usable power in that service. A 200amp service can provide up to 400 amps. Yes you may need an upgrade (you'd have to do a survey) but remember that you do have 100 amps available on both phases. 

As far as the panel being 100amps, keep in mind that each phase can supply up to 100 amps. So you really have 200amps of usable power in that service. A 200amp service can provide up to 400 amps. Yes you may need an upgrade (you'd have to do a survey) but remember that you do have 100 amps available on both phases. 

True for 110 volt circuits.  But a 220 volt circuit like this compressor draw power from both phases.